The present invention relates to a system for the efficient use of low voltage current supplied by a battery that is coupled to a battery charger onboard an extracting machine for the mining of coal or ore. More particularly, the present invention relates to a control system which disconnects the low voltage current from the battery to one of two groups of devices which are unessential at times when the extracting machine is non-operational and therefore the battery is not being charged by the high voltage current supply.
As is known in the art, it has already been proposed to equip extracting machines, especially drum-cutting machines, with an onboard battery which can be charged by an electrical system coupled to the power supply lines in a trailing cable. Among other things, such a battery has been used to supply electrical power for monitoring and fault-indicating devices on the extracting machine as well as for a memory store section of an onboard computer. Moreover, the battery is utilized to produce a warning signal typically by means of a horn, which is sounded when the drive motor is being started. This warning signal provides an indication to operating personnel in the immediate vicinity of the mining machine that the drive motor is about to be started up and that the mining cutters are about to work on the mine face.
During the operation of the extracting machine, the onboard battery thus continuously supplies electrical energy to two groups of electrical load devices. The first of these groups consists of electrical devices which become non-functional at the time when the extracting machine is at rest and non-operational. The electrical load devices belonging to the second group must remain functional even though the machine is at rest. The devices belonging to the second group include a plurality of means for providing measurements of operating parameters including measurements taken during the preceding cutting operation and indicators associated therewith to enable a continuous indication of such information to operating personnel. While not so limited, the present invention is particularly adapted to include the use of indicating apparatus of the type shown and described in copending application Ser. No. 398,422.
The underground site requirements and conditions place restrictions which dictate that an underground extraction machine must be constructed in a compact manner. This restricts available space and it places narrow limitations to the possibilities for housing a chargeable battery within the body of the extracting machine. Therefore, the physical dimensions of the battery must be held within specified limitations and this, of course, restricts the electrical storage capacity of the chargeable battery.